| 摘要 |
PROBLEM TO BE SOLVED: To provide a styrene-based copolymer excellent in mechanical strength, moldability and impact strength and having a moderate softening temperature, a resin composition comprising the styrene-based copolymer and a shrink film excellent in mechanical strength, moldability and impact strength and having a moderate softening temperature. SOLUTION: There is provided a styrene-based block copolymer comprising in one molecular chain a styrene-based polymer segment comprising a polymer of a styrene compound and a random copolymer segment of a styrene compound and an acrylic ester compound, where a number average mol.wt. (Mn) in terms of polystyrene is 20,000 or more, a mol.wt. distribution (Mw/Mn), represented by the ratio of a weight average mol.wt. (Mw) in terms of polystyrene to Mn, is 1.4-3.0, the ratio of the styrene-based polymer segment in the whole copolymer is 5-95 wt.% and the amount of copolymerized styrene compound units in the whole copolymer is 5-95 mol.%. |
